The dio keyword for enabling the extension is missing in the new dev-lang/php-5 packages.
Created attachment 71076 [details, diff] php5_0-sapi.eclass patch
Uhm... http://www.php.net/dio <snip> "This extension is only available on Windows Platforms as of PHP 5.0.0" </snip> and further: <snip> Note: This extension has been moved to the PECL repository and is no longer bundled with PHP as of PHP 5.1.0. </snip>